CA2130581A1

CA2130581A1 - Plastic spring assembly

Info

Publication number: CA2130581A1
Application number: CA002130581A
Authority: CA
Inventors: Wilhelmus J. J. Maas; Petrus L. W. Hurkmans
Original assignee: Individual
Current assignee: AFA Products Inc
Priority date: 1992-02-24
Filing date: 1993-02-23
Publication date: 1993-09-02
Also published as: GB9416757D0; NL9320027A; GB2278406B; DE4390813T1; LU88523A1; NZ251123A; TW253844B; IL104784A; GB2278406A; AU3795793A; AU666361B2; MX9301010A; IL104784A0; JPH07504146A; WO1993016954A1

Abstract

ABSTRACT

The trigger operated pumping mechanism (49) comprises a body (14), a cylinder (48) in the body of a dispensing device (10); a piston (42) received in the cylinder (48); a trigger (32) movably mounted to the body (14) and having a front side and back side (415), and being coupled to piston (42); and a non-metal biasing mechanism (40) for biasing the trigger (32) away from the body (14) to bias the piston (42) coupled to the trigger (32) out of the cylinder (48), the biasing mechanism (40) including a non-coiled, elongate, generally flat, spring mechanism (40,640) having opposite ends (410 or 642; 414 or 644) and being positioned between the body (14) and the trigger (32).

Description

:' `~` 1 PLASTIC SPRING ASSEMBLY
BACKGROUND OF THE INVENTION
1. Field of the Invention.
The present invention relates to a trigger operated 5 dispensing de~ice for mounting to the top neck of a storage container. Although such devices, known as trigger sprayers, can be reused, often times they are disposed of.
The trigger sprayer includes a body, and a pumping mechanism comprising a trigger movably mounted to the body, a 10 piston releasably coupled to the trigger and a cylinder in the : body for receiving the piston for pumping fluid and defining a - pumping chamber. The cylinder extends to a fixed back wall in the body, whereby the space between the back wall and the inner end of the movable piston defines a variable volume pumping 15 chamber. The cylinder has a fluid inlet valve and a fluid outlet valve associated with the back wall;
- To facilitate disposal and/or recycling of the sprayer, the trigger sprayer of the present invention is made of non-metal, plastic or synthetic parts.
This is achieved by mounting a synthetic/plastic return spring which forms part of the pumping mechanism between the trigger and the sprayer body. This is also achieved by providing plastic inlet and outlet flap valves associated with the back wall of the cylinder.
25 2. Description of The Prior Art.
It is well known in the art of tri.gger sprayers to mount a metal spring in a pumping chamber of a pumping mechanism in a tri.gger sprayer. The spring acts against a piston coupled to the trigger for urging the trigger to it's home, at rest, 30 position when the trigger i9 released.
Hereto~ore, it has also been proposed to provide plastic springs or flexures in trigger sprayers. Some examples of these previously proposed trigger sprayers are disclosed in the following patents;
U.S. Patent No. Patentee 4,915,263 Corba 4,898,307 Tiramani 4,624,413 Corsette 4,593,607 Bennett ~0 4,273,290 Quinn -eubstitute sheet-4,241,853 Pauls et al.
4,191,3I3 slake et al.
SUMMARY OF THE INVENTION
According to the present invention there is provided a trigger operated pumping mechanism for a fluid dispensing device comprising a body adapted to be mounted to a container.
The pumping mechanism comprises: a cylinder in the body of the dispensing device; a piston received in the cylinder; a trigger 10 movably mounted to the body and having a front side and a back side, and being coupled to the piston; and a non-metal biasing ; mechanism for biasing the trigger away from the body to bias the piston coupled to the trigger out of the cylinder, the biasing mechanism including a separate, non-coiled, elongate, 15 generally flat, spring mechanism having elongate, opposed flat surfaces and opposite ends and being positioned between the body and the trigger; the trigger back side having a back wall surface; and, the spring mechanism having one flat surface on one end portion at one end of the spring mechanism positioned 20 adjacent the back wall of the trigger and having the other end of the spring rnechanism positioned rearwardly of the trigger and engaging against the body.

BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 i9 a perspective view of a trigger sprayer constructed according to the teachings of the present invention.
FIG. 2 i9 an exploded perspective view of the trigger sprayer shown in FIG. l and shows a locking ring prior to its 30 detachment from a cylindrical base of the sprayer body.
FIG. 3 is a vertical sectional view of the trigger sprayer in its at rest position where a spring between a trigger and the sprayer body biases the tri~ger and a piston rod coupled thereto to the most outward position.
' ` 35 FIG. 4 ig a vertical sectional view of the trigger sprayer similar to the view shown ln FIG. 3 but showing the trigger fully depressed.
FIG. 5 is perspective view of a non-metal trigger sprayer spring assembly of the trigger sprayer shown in FIG. 1.
-~ub~titute sheet-, ~ ~
FIG. 6 is a side view of the spring assembly shown in FIG.
5.
FIG. 7 is a top plan view of the spring assembly shown in FIG. 5.
FIG. 8 is a top plan view of another embodiment of the spring assembly constructed according to the teachings of the present invention.
FIG. 9 is a side view of the spring assembly shown in FIG.
8.

FIG. 10 is a bottom plan view of the spring assembly shown in FIG. 8.
- ~
DESCRIPTION OF THE PREFERRED EMBODIMENT(S) Referring now to the drawings in greater detail, there is 15 illustrated in FIG. 1 a perspectiv~ view of an all synthetic/plastic trigger sprayer 10 coupled to a bottle 12.
An exploded perspective view of the parts of the trigger sprayer 10 is shown in more detail in FIG. 2.
The trigger sprayer 10 includes a body 14, a nose bushing 20 16 at a discharge end 18 of the body 14, a nozzle tamper proof pull away piece 20, a top portion 22 and a hand gripping formation 24 extending rearwardly from the top portion 22 of the body 1~ and then downwardly to a cylindrical base 26 of the body 14. The base 26 is held by a locking ring 28 to a neck 30 25 of the bottle 12.
A trigger 32 having a front side 31 is pivotally mounted to the body 14 by having two cylindrical pins 34, molded on the top end of two opposed side walls 36 of the trigger 32, inserted into two corresponding holes 38 in the body 14 of the 30 trigger sprayer 10.
As shown in FIG. 2, a plastic spring assembly 40 is placed between the body 14 and the trigger 32 to urge the trigger 32 always back into its home position. Coupled to the trigger 32 is'a piston~2 having an outer piston rod 44 which connects 35 with the trigger 32 and an inner cylindrical end 46 which is received in a cylindrical opening 48 in the body 14 for the purpose oE varying the volume in a pumping chamber defined in the opening 48.
-substitute sheet-The trigger 32, the spring assembly 40, the piston 42 and the cylindrical opening 48 form and define primary components of a pumping mechanism 49.
A valve intake stem 50 is received into the bottom of the 5 cylindrical base 26 and has a dip tube 52 releasably fixed thereto and depending therefrom for insertion into the bottle 2.
A safe and child resistant sprayer/bottle connection is provided and includes locking tabs 53 with lug receiving 10 openings 54 formed in the cylindrical side wall of the ; cylindrical base 26 and locking lugs on the bottle neck 30 and locked in place by the locking ring 28.
When the molded sprayer body is removed from a mold, the locking ring 28, connected to the cylindrical base 26 of the 15 body 14 by six links, points, fillets or webs 57 which are necessary for molding the locking ring 28 together with the body 14, is broken away from the cylindrical base 26 by breaking the fillets 57 and moved upwardly on the base 26.
During assembly of the parts of the trigger sprayer 10, the 20 locking ring 28 is moved downwardly over the cylindrical base 26.
A nozzle assembly 58 is provided and includes a rotatable nozzle cap 60 having a forwardly extending cylindrical extension 62. The nozzle cap 60 is mounted on the nose bushing 25 16 extending from a cylindrical por~ion 64 of the body 14 and includes an annular band 66 for holding the nozzle cap 60.
Three different positions of the nozzle cap 60, a STOP
position, a SP~AY position, and a STREAM position are provided.
When the nozzle assembly 58 is mounted to the body 14, a 30 mounting block 67 of the piece 20 is snap fittingly received through an opening o8 in the top portion 22. ~t the same time, fork arms 69 of the piece 20 extend through notches 70 in the top portion 22 and~or notches 71 in the top wall of the cap 60 between one of two flexible locking legs or prongs 72 and the 35 cylindrical portion 64 for securing the nozzle cap 60 in its STOP position, thereby ensuring a tamper proof and child resistant locking of the trigger sprayer nozzle assembly 58 to the body 14.
-~ubstitute sheet-The nozzle assembly 58 is mounted on the discharge end 18 of trigger sprayer lo, as described above. The top portion 22 of the body 1~ extends rearwardly to a rear end 73 of the hand gripping formation 24 and then slants forwardly and downwardly from the rear end 73 to the cylindrical base 26.
The six contact fillets or webs 57 are uniformly distributed around the lower end of the cylindrical base 26 and are initially integral with the locking ring 28. During the molding process, the contact fillets or webs 57 are broken and 10 the locking ring 28 is moved upwardly relative to the cylindrical base 26. Later, when the locking ring 28 is moved .. `-`
downwardly on the base 26, an annular groove 74 within the ~ `
locking ring 28 snap-fittingly mates with an annular rib 75 on .---.. -the base 26. The upper position of the locking ring 28 is the 15 pre-application-to-a-bottle position and the locking ring 28 ls held in this position by frictional engagement of the inner ..
wall of the locking ring 28 with the rib segments 76 provided on the outer cylindrical wall of the cylindrical base 26. The upper, partially annular rib segments 76 on the outer 20 cylindrical wall of the cylindrical base 26 locate and to some extent limit upward movement of the locking ring 28.
As shown in FIG. 3, molded within the cylindrical base 26 to a top wall 31~ of the cylindrical base 26 is a small diameter seal ring 316. The seal ring 316 i9 designed to seal 25 against the inner diameter of the bottle neck 30. The seal ring 316 has a bevelled end 318 at its lower side to facilitate insertion of the bottle neck 30 into the base 26 and around the seal ring 316.
Within the inner area of seal ring 316 is an opening 320, 30 having a shape according to the shape of the intake stem 50 which i.s generally oval in cross-section. The intake stem 50 is press-fitted into the opening 320 until ridges 322 on the i.ntalce stem 50 snap into mating mounting groove~ on the inner , su~l-face oE the wall of the opening 320. In this way, an air 3~ tight seal is provided. The diptube 52 is releasably fixed in the center of the intake stem 50. The length of the diptube 52 depends on the size of the bottle 12. However, it is recommended that the diptube 52 should extend to the bottom of . .
-~ub~titute ~heet-the bottle 12 but shouldn't touch it.
The cylindrical opening 48 is located inside the body 14 of the trigger sprayer 10. The piston cylindrical end 46 fits tightly into the cylindrical opening 48 to create a pumping 5 chamber 324 having a variable volume between a fixed back wall 326 of the cylindrical opening 48 and a rearwardly facing wall 328 of the piston cylindrical end 46. The fixed wall 326 of the pumping chamber 324 has an inlet flap valve 330 situated in the lower part thereof and an opening 332 in the upper part lo thereof. An orifice 334 through a wall of the intake stem 50 : is located to mate or register with the inlet flap valve 330 - and to establish an inlet passageway. The inlet passageway is provided by the hollow diptube 52, the intake stem 50 and the orifice 334.
15The opening 332 is located to mate or register with an outlet flap valve 336 on the top side of intake stem 50. Inlet flap valve 330 and outlet flap valve 336 control the fluid flow into and out of pumping chamber 324.
The trigger 32 is pivotally mounted on the body 14 of the trigger sprayer 10 by inserting the two laterally extending pins 34 on the upper part of the trigger 32 into the two corresponding holes 38 in the body 14.
As shown in FIG. 4, the plastic spring assembly 40 has a flat tapered end 410 press-fitted into a recess 412 in the body 25 14 located underneatll an inner end of the cylindrical portion 64 of the body 14. Another end 414 of the plastic spring assembly 40 i~ placed in a trough-like space 416 in the back side of the trigger 32 against a back wall 415. The plastic spring assembly ~0 is bent and remains under stress to urge the trigger 32 always back into its home position.
FIG. 4 shows the trigger sprayer 10 with the trigger 32 pressed in by the operator. The pressure in the pumping chamber 324 opens outlet flap valve 336 so that the fluid can Ielave pumping chamber 324. At the same time, the plastic 35 spring assembly 40 is bent and stressed even more, but it is not stretched above its Hook limit, and the operator needs a maximum force to keep the trigger 32 pressed in.
After the operator stops pressing trigger 32, the plastic -~ubstltute ~heet-spring assembly 40 urges the trigger 32 together with piston 42 bac~ into their home positions. While the piston 42 moves back, a vacuum arises inside the pumping chamber 324. This vacuum opens inlet flap valve 330 and sucks in fluid from the 5 bottle 12.
When the fluid is sucked out of the bottle 12, and because the bottle 12 and the trigger sprayer lO connection is air tlght, a vacuum arises within the bottle 12. To avoid a vacuum within the bottle 12, a venting system is provided. The 10 venting system includes a vent hole 344 in the top wall 314 of the cylindrical base 26. This part of the top wall 314 defines - a ~all area between the lower side of the cylindrical opening 48 inside body 14 of trigger sprayer 10 and a cylindrical cavity 346 within cylindrical base 26. When the trigger 32 is lS fully pressed in, vent hole 3~4 is opened and a fluid connection between the inside of the bottle 12 and the atmosphere is established so that air is able to get into the bottle 12. When the trigger 32 is not pressed in, e.g. when it is in its home position, the vent hole 344 is covered by the 20 cylindrical end 46 of the piston 42 to close the vent hole 344 thereby preventing fluid from coming out of the bottle 12.
The pumping chamber 324 is designed so that, the ~dead volume'~, i.e. the minimum volume of the pumping chamber 324, is very small, 1/20 to 1/4 the full volume of pumping chamber 324.
25 With a small dead volume, only a very little amount of the fluid or air i~ left in the pumping chamber 324, after the trigger 32 is ~ully pressed in. This construction minimizes the size o~ compressible air space inside the pumping chamber 324 and allows the trigger sprayer 10 to build higher 30 compression against the flap valve 330 during the priming of the trigger sprayer lO. This minimized "dead volume" provides for ~uicker priming of the trigger sprayer lO and higher vacuum and high compression during the intake and ejection strokes.
Anotherl effect of the small "dead volume" is that the 35 pumping chamber 324 is filled up with fluid very quickly therefore reducing the number of initial strokes required to prime ~he trigger sprayer lO.
An outer end 510 of the piston rod 44 has a transversely -BUb~titUte B~eet-~- . 8 located cylinder 512. The cylinder 512 is located transversely to the longitudinal axis of the piston rod 44 between legs 513 and has an axially extending V in cross section slot 514 in the middle thereof for receiving a pivot edge 516 of a hook member 5 517 extending between the sides 36 of the trigger 32. The hook member 517 is part of a bearing formation 518 which is provided on the backside of trigger 32 between the sides 36 and which has an opening 519 through which the outer end 510 is received.
The cylinder 512 engages in the bearing formation 518 of the 10 trigger 32 and the sides of the V shaped slot 514 act as ~or ; form) stops to limit the rotational freedom of the connected - parts.
The bearing formation 518, in combination with the V
shaped slot 514, establish a movable trigger 32 - piston 42 15 connection with limited, but sufficient, rotational freedom.
This enables the piston 42 to be moved within the pumping chamber 324 while being pivotally connected to trigger 32 in a simple and efficient manner.
The bearing formation 518 includes two rounded bearing 20 seating surfaces 520 adjacent the inner side of each side 36 of the trigger 32 and between one side 36 of the trigger 32 and the hook member 517 at the top of the opening 519 and between one side 36 and a slot 521 on the bottom of the opening 519.
The cylindrical ends of the cylinder 512 seat and rotate on these bearing surfaces 520.
Referring now to FIGS. 5, 6 and 7, the spring assembly 40 includes two leaf springs 610 and 612 which are connected together at each end by a webbing 614 or 616. As shown in FIG.
6 the two springs 610, 612 are bowed slightly to form an upper 30 bowed spring 610 and a lower bowed spring 612. Each of these elongate sprin~s 610, 612 are molded integral to each other and then a separation or split 618 between them is formed by a splitting process or cutting process. Alternatively, the sp~ing assembly 40 can be a one piece molding comprising two 35 blade springs connected together at each end. Further, as shown, each spring 610 and 612 is beveled at its ends as indicated by reference numerals 620 and 621 for spring 610 adjacent to the respective webbing 614 or 616. Likewise the ...
-~ubstitute sheet-, :
lower elongate leaf spring 612 is beveled at 622 and 623 to the hinge or webbing 614 or 616 as shown.
Also, as best shown in FIG. 7, the end portions of each spring 610, 612 are tapered toward the webbing 614 or 616 and 5 each spring 610, 6~2, is wider in a middle portion indicated by reference numeral 625.
The lower elongate leaf spring 612 has a notch 626, 627 formed at each end thereof to define a shoulder 628 or 629.
The spring assembly 40 with the ends o~ the springs 610 10 and 612 formed in the manner described above define the mirror-: image ends 410 and 414, each of which is configured to fit into - the recess 412 with the shoulder 628 or 629 being adapted to engage or hook with a shoulder adjacent the lower outer end of the recess 412 as shown in FIGS. 3 and 4.
The leaf springs 610, 612 are made of glass fiber reinforced plastic material such as a mixture of polypropylene and polyamide (nylon) plus 30~ by weight glass fibers.
Another embodiment of a spring assembly 640 constructed according to the teachings of the present invention is shown in 20 FIGS. 8, 9 and 10. The spring assembly 640 has opposite ends 642 and 644, only one of which, the end 642 is adapted to be received in the recess 412. The spring assembly 640 includes an upper or elongate blade or leaf spring 646 and a lower elongate blade or leaf spring 648.
The ends 642 and 644 of the leaf springs 646 and 648 of the spring assembly 6~0 are beveled and tapered as in the spring assembly 40 shown in FIGS. 5-7. At the end 642, which is received in the recess 412, a hinge or web connection 650 is provided between the leaf springs 646 and 648. However, at the 30 other end 6~4 the leaf springs 646 and 648 are connected by a cylindrical loop 652. The loop 652 is compressed when the trigger 32 is pushed against the outer surface of the blade leaf spring 6~6 adjacent the end 644 of the spring assembly ,~ 640.
As best shown in FIGS. 9 and 10, the lower leaf spring 648 has only one notch 654 on the outer surface thereof adjacent the end 642. Also, spaced inwardly of the notch and extending downwardly from the outer surface of the blade 648 is a small -sub~titute sheet-r; ~ 1 0 post 656 which serves to limit inward movement of the spring -asse~bly-into the recess 412 and to limit downward movement of the spring assembly 640 in use.
As shown in FIGS. 3 and 4, the spring assembly 40 or 640 is received between the bearing formation 518 and the back side 415 of the front wall 31 of the trigger 32 with the end 410 or . . -:
642 received in the recess 412 and the outer surface of the .-upper blade 610 or 646 bearing against the inner wall surface 415 of the front wall 31 of the trigger 32 in the trough area .
10 416.
In use, the spring action is obtained by posit~oning the ---end 410 or 642 in the recess 412, by positioning the spring -~
assembly 40 or 640 in the trough area 416 and between the bearing formation 518 and the back side 415 of the front wall --- - `
15 31 of the trigger 32, and by the sliding action of the outer : surface of the blade 610 or 646 adjacent end 414 or 644 against the back side 415 of the front wall 31 of the trigger 32. ~:

':
`'``

~ -substitute eheet-.

Claims

11 WE CLAIM:

1. (Amended) A trigger operated pumping mechanism for a fluid dispensing device said pumping mechanism comprising:
a body extending from a discharge end rearwardly of the fluid dispensing device toward a hand gripping formation of the fluid dispensing device;
said body having a hollow cylinder therein extending to a rear wall;
a piston received in said cylinder;
a trigger movably mounted to said body and having a front side and a back side, and being coupled to said piston; and biasing means for biasing said trigger away from said body to bias said piston coupled to said trigger out of said cylinder, said biasing means including non-metal, non-coiled, elongate spring means having opposite ends and being positioned between said body and said trigger; and, said spring means extending rearwardly from said trigger toward the hand gripping formation and having one end of said spring means positioned adjacent to and acting against said trigger and said other end of said spring means being positioned rearwardly of said trigger adjacent said body at a location which is close to said rear wall of said cylinder.

2. (Same) The pumping mechanism of claim 1 wherein said biasing means includes at least one elongate flat spring made of glass fiber reinforced plastic.

3. (Same) The pumping mechanism of claim 1 wherein said biasing means is a spring leaf assembly including two elongate leaf springs.

4. (Same) The pumping mechanism of claim 3 wherein said leaf springs are connected together at each end.

5. (Same) The pumping mechanism of claim 1 wherein said body has a recess above said cylinder for receiving the other end of said spring means; said trigger back side has a back wall; and said spring means has a flat surface adjacent said one end of said spring means for slidably engaging said back wall of said trigger and the other end of said spring means having a shape configured to be received in said recess.

6. (Amended) The pumping mechanism of claim 3 wherein said body has a recess above said cylinder for receiving the other end of said spring assembly and at least the other of said leaf springs of said spring assembly has a sharp cornered notch adjacent each end and an edge of said recess has a shoulder for engaging one notch for holding said other end of the spring assembly in said recess.

7. (Same) The pumping mechanism of claim 6 wherein each end of each leaf spring is inclined on one side thereof to a blunt end and each leaf spring is wider in the center than at the ends.

8. (Amended) The pumping mechanism of claim 1 further comprising:
a piston rod formation extending outwardly from said piston and having an outer end;
first coupling means on said outer end of said piston rod formation for coupling to said trigger comprising a transversely extending short cylinder;
second coupling means on said back side of said trigger for releasably coupling to said first coupling means on said piston rod formation in a snap-fitting manner, said second coupling means comprising a bearing formation in said back side of said trigger for receiving and engaging said short cylinder and connecting means for snap-fittingly engaging with said short cylinder.

9. (New) The pumping mechanism of claim 8 wherein said said short cylinder has a V-shaped notch in, and extends axially of said short cylinder, and said connecting means of second coupling means comprises a hook member positioned to extend into said V-shaped notch and having a V in-cross-section outer end for being received in said V-shaped notch.

10. (New) The pumping mechanism of claim 9 wherein said V-shaped notch has an angle at the vertex of the V sufficiently larger than the angle of the vertex of the V of said V in-cross-section outer end of said hook member to permit said outer end of said hook member to rotate on said V-shaped pivot seat during movement of said trigger from its home position to its fully squeezed in position.

11. (New) The pumping mechanism of claim 1 wherein said dispensing device includes outlet means and means for coupling said dispensing device to a container and wherein said body, said piston, said trigger, said outlet means and said coupling means are all made of non-metal recyclable materials.